The present invention relates generally to an improved coating formulation, and more particularly to a water-based film former which may be applied to a variety of surfaces through a variety of application techniques or systems, and which is capable of forming a thick coating with highly desirable adherent and coherent properties. The uncured material is highly adherent to the surface upon which it is applied while it remains in liquid state. Once 10 the material has been applied and permitted to cure, the residual thick coating or film possesses sufficiently high cohesive strength so as to render the dried film extremely tough and durable, and with sufficiently high adhesive strength so as to render the coating resistant to peel or other premature failure or release. When the coating material has dried or otherwise cured through reaction and solvent (water) removal, a durable, pliable, and yet tough coating is created. This coating is created without premature surface curing or skinning which would otherwise impede the loss of excess solvent from an uncured core. This coating has been found highly adaptable for application to flexible articles, particularly articles fabricated from plastic, including plastic in foam form. Application techniques for the adhesive while in liquid form are wide and varied, and may include dipping, brush application, or spray application. Coatings of from as thin as about 2 mils but preferably from about 8 mils in thickness and up to about 12 to 15 mils may be obtained with a single dipping of an article into the formulation.
In the preparation of conventional coating formulations, it is generally desired that the film forming layer, particularly when in cured form, have appropriately matched adhesive and cohesive properties. Normally, theses properties are matched so that the bond which is formed by the adhesive material preferably fails due to simultaneous failure of both its adhesive and its cohesive properties. At the same time, it is generally desirable that the conventional film possess a relatively high peel strength. The formulations of the present invention are designed to possess high adhesive and cohesive strength so as to provide for coating and/or film durability. Additional features of the formulations of the present invention include the characteristic of preparing reliable coatings through dipping of foam plastic articles, thereby facilitating the coating of these otherwise difficult-to-coat articles. The desirable adhesive quality of the materials of the present invention appear to make these coating operations possible. By way of example, the consistency of the liquid coating material permits coating of the object being coated in single or multiple dips, with a thick and durable film being prepared thereby. Films having such properties are particularly desirable for the coating of plastic foam articles, with the formulations of the present invention also being desirable for use as film formers for coating other articles, such as rigid metallic articles and the like. Films and coatings formed in accordance with the present invention retain their good physical properties, including flexibility and durability, over extended periods of time.
As indicated above, the coatings of the present invention have wide application to coating of articles fabricated of plastic, including plastic foam articles. These coatings may be employed to form coatings for objects fabricated from polyvinylchloride, polyethylene, including polyethylene foam in lineal, radiated cross-linked and chemically cross-linked form, polypropylene, expanded polystyrene, styrofoam, and the like.